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contains

Note

This is a point-in-time snapshot of the API documentation from January 2026. Going forward, we will not be maintaining a public copy of these references, and recommend users to refer to the built-in signature helpers available in the Hack LSP instead for complete and up-to-date information.

Determines if the specified key is in the current ImmMap

public function contains(
  mixed $key,
): bool;

This function is interchangeable with containsKey().

Guide​

Parameters​

  • mixed $key

Returns​

  • bool - true if the specified key is present in the current ImmMap; false otherwise.

Examples​

See Map::contains for usage examples.